test for #494 (canonicalization sometimes collapses BNodes)

1 files changed, 103 insertions, 4 deletions

diff --git a/test/test_canonicalization.py b/test/test_canonicalization.py
index 2745f490..30fb0bb1 100644
--- a/test/test_canonicalization.py
+++ b/test/test_canonicalization.py
@@ -37,10 +37,10 @@ def negative_graph_match_test():
     True
     ],
     [ unicode('''@prefix : <http://example.org/ns#> .
-     :linear_two_step_symmetry_start :related [ :related [ :related :linear_two_step_symmatry_end]], 
+     :linear_two_step_symmetry_start :related [ :related [ :related :linear_two_step_symmatry_end]],
                                               [ :related [ :related :linear_two_step_symmatry_end]].'''),
     unicode('''@prefix : <http://example.org/ns#> .
-     :linear_two_step_symmetry_start :related [ :related [ :related :linear_two_step_symmatry_end]], 
+     :linear_two_step_symmetry_start :related [ :related [ :related :linear_two_step_symmatry_end]],
                                               [ :related [ :related :linear_two_step_symmatry_end]].'''),
     True
     ],
@@ -68,7 +68,7 @@ def negative_graph_match_test():
           ].'''),
     False
     ],
-    # This test fails because the algorithm purposefully breaks the symmetry of symetric 
+    # This test fails because the algorithm purposefully breaks the symmetry of symetric
     [ unicode('''@prefix : <http://example.org/ns#> .
      _:a :rel [
          :rel [
@@ -148,4 +148,103 @@ def negative_graph_match_test():
         print digest2
         assert (digest1 == digest2) == identical
     for inputs in testInputs:
-        yield fn, inputs[0], inputs[1], inputs[2]
\ No newline at end of file
+        yield fn, inputs[0], inputs[1], inputs[2]
+
+def test_issue494_collapsing_bnodes():
+    """Test for https://github.com/RDFLib/rdflib/issues/494 collapsing BNodes"""
+    g = Graph()
+    g += [
+        (BNode('Na1a8fbcf755f41c1b5728f326be50994'),
+         RDF['object'],
+         URIRef(u'source')),
+        (BNode('Na1a8fbcf755f41c1b5728f326be50994'),
+         RDF['predicate'],
+         BNode('vcb3')),
+        (BNode('Na1a8fbcf755f41c1b5728f326be50994'),
+         RDF['subject'],
+         BNode('vcb2')),
+        (BNode('Na1a8fbcf755f41c1b5728f326be50994'),
+         RDF['type'],
+         RDF['Statement']),
+        (BNode('Na713b02f320d409c806ff0190db324f4'),
+         RDF['object'],
+         URIRef(u'target')),
+        (BNode('Na713b02f320d409c806ff0190db324f4'),
+         RDF['predicate'],
+         BNode('vcb0')),
+        (BNode('Na713b02f320d409c806ff0190db324f4'),
+         RDF['subject'],
+         URIRef(u'source')),
+        (BNode('Na713b02f320d409c806ff0190db324f4'),
+         RDF['type'],
+         RDF['Statement']),
+        (BNode('Ndb804ba690a64b3dbb9063c68d5e3550'),
+         RDF['object'],
+         BNode('vr0KcS4')),
+        (BNode('Ndb804ba690a64b3dbb9063c68d5e3550'),
+         RDF['predicate'],
+         BNode('vrby3JV')),
+        (BNode('Ndb804ba690a64b3dbb9063c68d5e3550'),
+         RDF['subject'],
+         URIRef(u'source')),
+        (BNode('Ndb804ba690a64b3dbb9063c68d5e3550'),
+         RDF['type'],
+         RDF['Statement']),
+        (BNode('Ndfc47fb1cd2d4382bcb8d5eb7835a636'),
+         RDF['object'],
+         URIRef(u'source')),
+        (BNode('Ndfc47fb1cd2d4382bcb8d5eb7835a636'),
+         RDF['predicate'],
+         BNode('vcb5')),
+        (BNode('Ndfc47fb1cd2d4382bcb8d5eb7835a636'),
+         RDF['subject'],
+         URIRef(u'target')),
+        (BNode('Ndfc47fb1cd2d4382bcb8d5eb7835a636'),
+         RDF['type'],
+         RDF['Statement']),
+        (BNode('Nec6864ef180843838aa9805bac835c98'),
+         RDF['object'],
+         URIRef(u'source')),
+        (BNode('Nec6864ef180843838aa9805bac835c98'),
+         RDF['predicate'],
+         BNode('vcb4')),
+        (BNode('Nec6864ef180843838aa9805bac835c98'),
+         RDF['subject'],
+         URIRef(u'source')),
+        (BNode('Nec6864ef180843838aa9805bac835c98'),
+         RDF['type'],
+         RDF['Statement']),
+    ]
+
+    print 'graph length: %d, nodes: %d' % (len(g), len(g.all_nodes()))
+    print 'triple_bnode degrees:'
+    for triple_bnode in g.subjects(RDF['type'], RDF['Statement']):
+        print len(list(g.triples([triple_bnode, None, None])))
+    print 'all node degrees:'
+    g_node_degs = sorted([
+        len(list(g.triples([node, None, None])))
+        for node in g.all_nodes()
+    ], reverse=True)
+    print g_node_degs
+
+    cg = to_canonical_graph(g)
+    print 'graph length: %d, nodes: %d' % (len(cg), len(cg.all_nodes()))
+    print 'triple_bnode degrees:'
+    for triple_bnode in cg.subjects(RDF['type'], RDF['Statement']):
+        print len(list(cg.triples([triple_bnode, None, None])))
+    print 'all node degrees:'
+    cg_node_degs = sorted([
+        len(list(cg.triples([node, None, None])))
+        for node in cg.all_nodes()
+    ], reverse=True)
+    print cg_node_degs
+
+    assert len(g) == len(cg), \
+        'canonicalization changed number of triples in graph'
+    assert len(g.all_nodes()) == len(cg.all_nodes()), \
+        'canonicalization changed number of nodes in graph'
+    assert len(list(g.subjects(RDF['type'], RDF['Statement']))) == \
+        len(list(cg.subjects(RDF['type'], RDF['Statement']))), \
+        'canonicalization changed number of statements'
+    assert g_node_degs == cg_node_degs, \
+        'canonicalization changed node degrees'